Centrifugal pipe casting apparatus



Feb. 2 8, 1933. s. B. CLARK A CENT-RIFUGAL PIPE CASTING APPARATUS original Filed May 9, 19:51

W/IWESS.

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UNITED STATES rArENr OFFICE STUART B. CLARK, Ol' RIVERTON, JERSEY, ASSIGNOR T0 UNITED STATES PIPE FOUNDRY COMPANY, OF BURLINGTON, NEW JERSEY, A CORPORATION OF -NEW JERSEY cEN'rnnuGAL HPF. CASTING APPARATUS Original application med lay 9, 1931, serial No. 536,159. Divided and this application led November 5,

1931. Serial No. 578,085. v

My invention has relation to the Well known method of casting pipes in which their power driven rotatable mold is associated with a relatively retractable runner for delivering molten metal to the mold, which at the beginning of the casting operation is fully inserted in the mold so as to deliver metal to its remote end-and whichY is retracted during the pouring operation so as to deliver the metal` progressively throughout the length -of the mold. A. typical machine adapted for the practice of this method of casting pipes is described in Patent No.

1,746,374, granted to J. H. Uhrig, February 11,1930. In the operation of such a machine it is customary to have the mold slightly tilted from the horizontal to facilitate the pouring operation and in consequence the flow of the metal delivered to the rotating mold is influenced not only by the centrifugal force applied to it by the rotating mold but also to some extent by gravity tending to cause the metal to ow in the direction of thev lower end of the mold, so that there is a certain longitudinal shifting of the molten metal in the mold during the casting operation which is unobjectionable during the casting of the main body of .the pipe but which during the casting of the final end ofthe pipe sometimes results in the thinning down of this end of the pipe to an objectionable extent.

While it is perhaps obvious that the tendency of the molten metal toflow longitudinally in the. mold can be counteracted to a large extent by increasing the speed of rotation of the meld, it has been found that material increase in the rotative speed of the mold over that found to be efficient in practice brings about a tendency to slip between the mold and the casting, which is apt to result in a defective casting. l

In my copending application for Letters Patent, filed May 9, 1931, Serial No. 536,159, of which this application isr a division, I

' have described and claimed a new method of operating pipe casting apparatus of the kind p above indicated, characterized in that the speed of rotation of the mold is' increased during the casting of the upper end of the pipe to such an extent as to counteract the tendpractice I increase the rotative speed dur` mg the pouring of the end of the pipe from` 5 to 50% depending on the fluidity and composition of the metal and as a concrete example in the casting of a 6 inch pipe I increase the speed of rotation during this stage of the casting operation from the normal speed of 500 revolutions per minute to 600 revolutions per minute, with the result thatv the production of defective pipes is materially reduced. Y l

The object of my present invention is to provide effective apparatus for the practice of myimproved method of casting and my invention consists in the provision of automatically acting means for increasing the speed of rotation of the mold during the final stage of the pipe casting operation and for this purpose I provide a device arranged to operate in timed relation with the retractive movements of the mold and runner and so connected with the rotating driving means of the mold as to speed up this rotative means during this final stage of the casting operation.

My invention will be better understood as described in connection with the drawing forming `part of this specification, in which Figure 1 is a diagrammatic illustration of a centrifugal pipe casting machine of the type to which my invention pertains and of automatic means for actuating the switch at a O'iven point in the travel of the mold, and

Iigure 2 is a diagrammatic showing of an electric system for controlling the speed of the motor.

In the drawinggA indicates the base of the machine which supports tracks or runners indicated at B, upon which a carriage C is movable, the tracks being inclined, as indi- 1, s99,3s3 i cated, to an angle of about 2 to a horizontal lane. The carriage C supports a water boX through which extends the centrifugal pipe mold E and the end E1 of the mold is -gear connected with a variable speed electric motor, indicated at F, so as to rotate the mold. G indicates the runner through which molten metal is poured into the mold, this runner being supported on the base of the machine by a frame O, which also supports the tilting iron ladle P. This runner is of such length that its delivery end when the carriage is moved to the extreme upper position extends nearly to the remote end of the mold. H is a switch operating finger, capable of longitudinal adjustment, secured to the mold carriage and I is an electric switch, mounted on the base A, and connecting electrically with the control panel of motor F. As shown in Fig. 2, the field of the motor has in series with it a variable resistance J. The switch I is normally closed, Which energizes a solenoid switch K to hold it in closed position, and the field circuit is from the line through line L, switch K, line M, a portion of resistance J, the field and back to the other side of the line. The amount of resistance cut in here determines the speed of the motor, it being understood that the greater the resistmeans operating to rotate the mold during the casting operation, the combination therewith of control mechanism for varying the speed of the means operative to rotate the mold and means operating in timed relation to the relative movements of the mold and runner, operative to adjust the control mechanism to increase the speed of the means for rotating the mold during the pouring of the spigot end of the pipe casting.

' STUART B. CLARK.

ance in the field circuit the greater the speed l of the motor.

In operation, the mold, being moved to the position -in which the runner extends through its length, is actuated at normal speed by the variable speed electric motor F and metal'is delivered to the runner G by ladle P and passes through it to the remoteend of the mold. The carriage supporting the mold is then retracted at regulated speed so that the pouring of the metal progresses throughout the length of the mold. When the carriage has reached the position in which the operating finger H engages the actuating arm of switch I, the circuit controlling switch K is broken. Thereafter the field circuit is compelled to take a path from the line through a variable connection N to the resistance J. This cuts in an adjustable amount of extra resistance and the motor speeds up'as desired to rotate the mold more rapidly.

The speed of the mold can of course be increased by hand manipulation of field rheostat controls.

After the rotation speed of mold has been increase-d, such increased speed should be maintained until the pouring is complete.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

In a centrifugal pipe casting machine comprisingv a rotatable mold held at a slight inclination to a horizontal'plane, a relatively retractable runner for delivering metal to the mold, operating t-o progressively deliver metal throughout the length of the mold and 

